The present invention relates to a quantum computing chip, and more specifically, to a signal port of the quantum computing chip.
In quantum computing, a quantum bit (qubit) is a quantum oscillator that eventually experiences unwanted decoherence in the form of dephasing and relaxation (T1 and T2 relaxation). Longer coherence times (larger values for T1 and T2) correspond with a longer time to perform quantum operations before the system decoheres. Several factors may contribute to the perturbations in the oscillation and hasten the T1 and T2 relaxation. A circuit comprising the qubits, resonators, and signal ports is formed as a thin film on a substrate. The substrate, typically formed of an insulating material with a high dielectric constant, may be viewed as a microwave resonator with chip resonant modes (chip modes). Signal ports are points on the circuit through which voltage may be applied to drive the circuit and output signals from the circuit are received. The chip modes may facilitate cross talk between ports. This cross talk may contribute to a noisy environment that leads to faster decoherence of the qubits. Further, in a multi-qubit architecture, the cross talk may lead to unwanted interactions between the qubits.